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Université de Fribourg

Zamolodchikov–Faddeev algebra and quantum quenches in integrable field theories

Sotiriadis, S. ; Fioretto, Davide ; Mussardo, G.

In: Journal of Statistical Mechanics: Theory and Experiment, 2012, no. 2, p. P02017

We analyze quantum quenches in integrable models and in particular we determine the initial state in the basis of eigenstates of the post-quench Hamiltonian. This leads us to consider the set of transformations of creation and annihilation operators that respect the Zamolodchikov–Faddeev algebra satisfied by integrable models. We establish that the Bogoliubov transformations hold only in the...

Université de Fribourg

X-ray two-photon absorption with high fluence XFEL pulses

Hoszowska, Joanna ; Szlachetko, Jakub ; Dousse, Jean-Claude ; Błachucki, W. ; Kayser, Yves ; Milne, Ch. ; Pajek, M. ; Boutet, S. ; Messerschmidt, M. ; Williams, G. ; Chantler, C. T.

In: Journal of Physics: Conference Series, 2015, vol. 635, no. 10, p. 102009

We report on nonlinear interaction of solid Fe with intense femtosecond hard x-ray free-electron laser (XFEL) pulses. The experiment was performed at the CXI end- station of the Linac Coherent Light Source (LCLS) by means of high- resolution x-ray emission spectroscopy. The focused x-ray beam provided extreme fluence of ~10⁵ photons/Ų. Two-photon absorption leading to K-shell hollow atom...

Université de Fribourg

X-ray study of structural domains in the near-surface region of SrTiO₃ substrates with Y0.6Pr0.4Ba₂Cu₃O₇/La2/3Ca1/3MnO₃ superlattices grown on top

Hoppler, Justin ; Stahn, J. ; Bouyanfif, Houssny ; Malik, Vivek Kumar ; Patterson, B. D. ; Willmott, P. R. ; Cristiani, G. ; Habermeier, H.-U. ; Bernhard, Christian

In: Physical Review B, 2008, vol. 78, no. 13, p. 134111

We investigated with synchrotron x-ray diffraction and reflectometry the formation of structural domains in the near-surface region of single crystalline SrTiO₃ (001) substrates with Y0.6Pr0.4Ba₂Cu₃O₇/La2/3Ca1/3MnO₃ superlattices grown on top. We find that the antiferrodistortive cubic to tetragonal transition, which occurs at...

Consortium of Swiss Academic Libraries

X-ray spectroscopy of stars

Güdel, Manuel ; Nazé, Yaël

In: The Astronomy and Astrophysics Review, 2009, vol. 17, no. 3, p. 309-408

Université de Fribourg

X-ray reflectivity theory for determining the density profile of a liquid under nanometre confinement

Perret, Edith ; Nygård, Kim ; Satapathy, Dillip K ; Balmer, Tobias E ; Bunk, Oliver ; Heuberger, Manfred ; Veen, J Friso van der

In: Journal of Synchrotron Radiation, 2010, vol. 17, no. 4, p. 465-472

An X-ray reflectivity theory on the determination of the density profile of a molecular liquid under nanometre confinement is presented. The confinement geometry acts like an X-ray interferometer, which consists of two opposing atomically flat single-crystal mica membranes with an intervening thin liquid film of variable thickness. The X-rays reflected from the parallel crystal planes (of known...

Université de Fribourg

X-ray reflectivity reveals equilibrium density profile of molecular liquid under nanometre confinement

Perret, E. ; Nygård, K. ; Satapathy, Dillip Kumar ; Balmer, T. E. ; Bunk, O. ; Heuberger, M. ; Veen, J. F. van der

In: Europhysics Letters, 2009, vol. 88, no. 3, p. 36004

A silane (tetrakis(trimethylsiloxy)silane) has been confined within a space of a few molecular diameters (9 Å) between two atomically flat opposing mica membranes. The liquid's electron density profile along the confinement direction has been determined by synchrotron X-ray reflectivity for film thicknesses of 8.58 and 11.22 nm. We find the liquid's molecules to be strongly layered at layer...

Consortium of Swiss Academic Libraries

X-ray photoelectron diffraction study of ultrathin PbTiO3 films

Despont, L. ; Lichtensteiger, C. ; Clerc, F. ; Garnier, M. G. ; Garcia de Abajo, F.J. ; Van Hove, M. A. ; Triscone, J.-M ; Aebi, P.

In: The European Physical Journal B - Condensed Matter and Complex Systems, 2006, vol. 49, no. 2, p. 141-146

Université de Fribourg

X-ray photoelectron diffraction study of Cu(1 1 1): Multiple scattering investigation

Despont, L. ; Naumović, Dusanka ; Clerc, F. ; Koitzsch, C. ; Garnier, M.G. ; Abajo, F.J. Garcia de ; Hove, M.A. Van

In: Surface Science, 2006, vol. 600, no. 2, p. 380-385

Multiple scattering theory based on a cluster model is used to simulate full-hemispherical X-ray photoelectron diffraction measurements in order to verify how state of the art multiple scattering simulations are able to reproduce the experiment. This approach is applied to the Cu(1 1 1) surface for two different photoelectron kinetic energies. Differences and similarities between single and...

Consortium of Swiss Academic Libraries

X-ray astronomy of stellar coronae

Güdel, Manuel

In: The Astronomy and Astrophysics Review, 2004, vol. 12, no. 2-3, p. 71-237